Comment by magicalist

> The Dune Encyclopedia, which was not written by him but which he said he considered canonical

No, he literally wrote in the intro to the book that it wasn't canon. It was a fan project and he thought that it was great there were fans doing things like that.

edit: and like with the terrible Dune prequels, the impulse to say "here's what really happened" usually diminishes what's interesting and powerful about oblique allusions in SF meant at least partly to function as a mirror on humanity.